Materials and Methods: Sixty male Wistar rats were randomly divided into 6 experimental groups. The control group (1) received no medications and surgery. The Sham group (2) had not received any medications; abdominal cavity was opened but no varicocele was induced. Varicocele group (3): abdominal cavity was opened, varicocele-induced and no medications were applied. In group 4 abdominal cavity was opened, varicocele-induced and animal received magnesium sulfate (25 mg/kg) for 6 weeks. The groups 5 and 6 were similar to group 4, except animals received 50 and 100 mg/kg of magnesium sulfate, respectively. At the end of the weeks 3 and 6, the abdomen was opened, semen samples were collected from the Caudal epididymis to determine epididymis weight, sperm mortality, mobility and sperm count.

Results: According to the results, experimental unilateral varicocele significantly diminished sperm mortality, mobility and sperm count compared to control and sham group (P < 0.05). Administration of magnesium sulfate as a medication dose dependently (25, 50 and 100 mg/kg) decreased sperm mortality and increased mobility and sperm count in experimental varicocele in rat compared to varicocele group at weeks 3 and 6 (P < 0.05).

Conclusion: According to the results, it seems, magnesium sulfate might improve sperm characteristics during varicocele.